Image Contrast In Microscopy:Interactive Tutorials

Background Intensity Effect on Contrast

Explore the effect of background intensity on image contrast in optical microscopy using this interactive tutorial. Instructions about how to operate the tutorial appear below the applet window.

To operate the tutorial, use the slider to vary the background intensity between a value of 0.01 and 1.00. As the slider is moved image contrast is calculated according to the equation:

Percent Contrast (C) = ((I(s) - I(b)) x 100)/I(b)

Where I(b) is the intensity of the background and I(s) is the specimen intensity. The tutorial plots image contrast as a function of image intensity and displays the contrast range for each background intensity selected by the slider. It becomes apparent after operating this tutorial that when background intensity is less than 0.1, small changes in image intensity produce large changes in contrast. As the background intensity is increased up to 1.0, changes in image intensity have a progressively smaller effect on overall contrast.